Susceptibility of grapevine rootstocks to Cylindrocarpon liriodendri and C. macrodidymum

The susceptibility of the grapevine rootstocks most commonly used in Spain to Cylindrocarpon liriodendri and C. macrodidymum was evaluated. Rooted cuttings of rootstocks 110-R, 1103-P, 140-R, 161-49C, 196-17C, Fercal and SO4 were inoculated by dipping their roots in conidial suspensions (5 × 105 conidia mL−1) of both pathogens and placed in a greenhouse. One month later, each plant was drench inoculated with 20 mL of the corresponding spore solution to guarantee root infection. After four months of incubation, root disease severity index (RSDI) and dry weights of shoot and root were recorded for each plant. RSDI was the best variable to show the effect of the inoculation with C. liriodendi and C. macrodidymum. According to this, all rootstocks inoculated were affected by the disease in some degree, being the rootstock 110-R the most susceptible to both pathogens.